Wisconsin Odonata Survey


Enallagma vesperum  Calvert, 1919
Vesper Bluet

Coenagrionidae, Pond Damsel Family

The bluets form a group of about 17 similar species in Wisconsin in which the males usually share the characteristics of having blue and black stripes on the thorax, and blue and black markings on the abdomen. In-hand examinations are usually needed to identify them, although they can be grouped into subcategories based on the amount of black showing on the abdomen. Males are easily identified, under magnification, by the shape of their terminal appendages. Females are generally duller than males, and they are more difficult to identify, which is accomplished by subtle differences in the shape of the mesostigmal plates on the top of the thorax. Generally, males are bright blue while the females are green or yellow-green or blue. There are some species that are yellow-orange, a mix of various colors, or black with some blue.


Global: G5     Wisconsin: S4    

Distinguishing Characteristics:

Varying from 1.1 to 1.5 inches in the length, this species is well known its yellow coloration. The male is yellow with broad black mid-dorsal stripe and thin black shoulder stripes. The abdomen is mostly black above except for some blue near the tip. The female is similar but duller yellow. Her abdomen is mostly black above with a pale tip.

Description of Habitat/Range:

This species ranges throughout eastern United States and southeastern Canada. They can be found at ponds and lakes and slow streams with emergent and aquatic vegetation, mainly in late afternoon to evening (dusk).

Flight Season:

The flight season extends from late May to early September in Wisconsin.

Shading illustrates monthly percentages of the total flight season records for the species. Each flight season record is a unique date/location/observer combination where one or more adult or an exuvia was recorded (excludes nymphs). The actual number of flight season records for each month is shown in parentheses.

Flight seasons begin earlier in the southern part of the state, often by a week or more. Also, flight charts may not be accurate for rare species because of few data available.
View user-submitted photos

(Click on photos to enlarge)
Photo of Male vesper bluet
Male vesper bluet. © Dan Jackson

Male vesper bluet
Photo of Male vesper bluet
Male vesper bluet. © John & Cindy Anderson

Male vesper bluet
Photo of Male vesper bluet with wide thoracic stripe variation
Male vesper bluet with wide thoracic stripe variation. © Dan Jackson

Male vesper bluet with wide thoracic stripe variation
Photo of Female vesper bluet
Female vesper bluet. © Dennis Paulson

Female vesper bluet

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